The experiments outlined in this proposal are designed to delineate the early period of Sindbis virus replication. Use of conditions which inhibit RNA synthesis will allow us to define viral activities as "early" or "late" based on their expression in the absence of RNA synthesis. Specifically, we intend to determine the intracellular location and stability of the parental induction of proteins and activities specified by the parental RNA. Induction of homologous interference, inhibition of host cell macromolecular synthesis, synthesis of viral polymerases and inhibition of cell division will be investigated. These studies will be facilitated by our recent finding that andenosine 3':5' cyclic monophosphate will reversibly inhibit viral RNA synthesis.